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<h2><span class="refentrytitle">Class template overloaded_function</span></h2>
<p>boost::overloaded_function &#8212; Function object to overload functions with distinct signatures. </p>
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<h2 xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv-title">Synopsis</h2>
<div xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv"><pre class="synopsis"><span class="comment">// In header: &lt;<a class="link" href="../reference.html#header.boost.functional.overloaded_function_hpp" title="Header &lt;boost/functional/overloaded_function.hpp&gt;">boost/functional/overloaded_function.hpp</a>&gt;

</span><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> F1<span class="special">,</span> <span class="keyword">typename</span> F2<span class="special">,</span> <span class="special">...</span> <span class="special">&gt;</span> 
<span class="keyword">class</span> <a class="link" href="overloaded_function.html" title="Class template overloaded_function">overloaded_function</a> <span class="special">{</span>
<span class="keyword">public</span><span class="special">:</span>
  <span class="comment">// <a class="link" href="overloaded_function.html#boost.overloaded_functionconstruct-copy-destruct">construct/copy/destruct</a></span>
  <a class="link" href="overloaded_function.html#id-1_7_2_2_1_5-bb"><span class="identifier">overloaded_function</span></a><span class="special">(</span><span class="keyword">const</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">function</span><span class="special">&lt;</span> <span class="identifier">F1</span> <span class="special">&gt;</span> <span class="special">&amp;</span><span class="special">,</span> 
                      <span class="keyword">const</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">function</span><span class="special">&lt;</span> <span class="identifier">F2</span> <span class="special">&gt;</span> <span class="special">&amp;</span><span class="special">,</span> <span class="special">...</span><span class="special">)</span><span class="special">;</span>

  <span class="comment">// <a class="link" href="overloaded_function.html#id-1_7_2_2_1_4-bb">public member functions</a></span>
  <span class="identifier">boost</span><span class="special">::</span><span class="identifier">function_traits</span><span class="special">&lt;</span> <span class="identifier">F1</span> <span class="special">&gt;</span><span class="special">::</span><span class="identifier">result_type</span> 
  <a class="link" href="overloaded_function.html#id-1_7_2_2_1_4_1-bb"><span class="keyword">operator</span><span class="special">(</span><span class="special">)</span></a><span class="special">(</span><span class="keyword">typename</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">function_traits</span><span class="special">&lt;</span> <span class="identifier">F1</span> <span class="special">&gt;</span><span class="special">::</span><span class="identifier">arg1_type</span><span class="special">,</span> 
             <span class="keyword">typename</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">function_traits</span><span class="special">&lt;</span> <span class="identifier">F1</span> <span class="special">&gt;</span><span class="special">::</span><span class="identifier">arg2_type</span><span class="special">,</span> <span class="special">...</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span>
  <span class="identifier">boost</span><span class="special">::</span><span class="identifier">function_traits</span><span class="special">&lt;</span> <span class="identifier">F2</span> <span class="special">&gt;</span><span class="special">::</span><span class="identifier">result_type</span> 
  <a class="link" href="overloaded_function.html#id-1_7_2_2_1_4_2-bb"><span class="keyword">operator</span><span class="special">(</span><span class="special">)</span></a><span class="special">(</span><span class="keyword">typename</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">function_traits</span><span class="special">&lt;</span> <span class="identifier">F2</span> <span class="special">&gt;</span><span class="special">::</span><span class="identifier">arg1_type</span><span class="special">,</span> 
             <span class="keyword">typename</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">function_traits</span><span class="special">&lt;</span> <span class="identifier">F2</span> <span class="special">&gt;</span><span class="special">::</span><span class="identifier">arg2_type</span><span class="special">,</span> <span class="special">...</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span>
<span class="special">}</span><span class="special">;</span></pre></div>
<div class="refsect1">
<a name="id-1.7.2.4.4"></a><h2>Description</h2>
<p>This function object aggregates together calls to functions of all the specified function types <code class="computeroutput">F1</code>, <code class="computeroutput">F2</code>, etc which must have distinct function signatures from one another.</p>
<p><span class="bold"><strong>Parameters:</strong></span> </p>
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<td><span class="bold"><strong><code class="computeroutput">F<span class="emphasis"><em>i</em></span></code></strong></span></td>
<td>Each function type must be specified using the following syntax (which is Boost.Function's preferred syntax): <pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"><span class="identifier">result_type</span> <span class="special">(</span><span class="identifier">argument1_type</span><span class="special">,</span> <span class="identifier">argumgnet2_type</span><span class="special">,</span> <span class="special">...</span><span class="special">)</span>
</pre>  </td>
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<p>In some cases, the <code class="computeroutput"><a class="link" href="make_overloaded_function.html" title="Function template make_overloaded_function">make_overloaded_function</a></code> function template can be useful to construct an overloaded function object without explicitly specifying the function types.</p>
<p>At least two distinct function types must be specified (because there is nothing to overload between one or zero functions). The maximum number of functions to overload is given by the  <code class="computeroutput"><a class="link" href="../BOOST_FUNCTIONAL_O_1_7_3_3.html" title="Macro BOOST_FUNCTIONAL_OVERLOADED_FUNCTION_CONFIG_OVERLOAD_MAX">BOOST_FUNCTIONAL_OVERLOADED_FUNCTION_CONFIG_OVERLOAD_MAX</a></code> configuration macro. The maximum number of function parameters for each of the specified function types is given by the  <code class="computeroutput"><a class="link" href="../BOOST_FUNCTIONAL_O_1_7_3_2.html" title="Macro BOOST_FUNCTIONAL_OVERLOADED_FUNCTION_CONFIG_ARITY_MAX">BOOST_FUNCTIONAL_OVERLOADED_FUNCTION_CONFIG_ARITY_MAX</a></code> configuration macro.</p>
<p><span class="bold"><strong>See:</strong></span> <a class="link" href="../boost_functional_overloadedfunction/tutorial.html" title="Tutorial"> Tutorial</a> section, <code class="computeroutput"><a class="link" href="make_overloaded_function.html" title="Function template make_overloaded_function">make_overloaded_function</a></code>,  <code class="computeroutput"><a class="link" href="../BOOST_FUNCTIONAL_O_1_7_3_3.html" title="Macro BOOST_FUNCTIONAL_OVERLOADED_FUNCTION_CONFIG_OVERLOAD_MAX">BOOST_FUNCTIONAL_OVERLOADED_FUNCTION_CONFIG_OVERLOAD_MAX</a></code>,  <code class="computeroutput"><a class="link" href="../BOOST_FUNCTIONAL_O_1_7_3_2.html" title="Macro BOOST_FUNCTIONAL_OVERLOADED_FUNCTION_CONFIG_ARITY_MAX">BOOST_FUNCTIONAL_OVERLOADED_FUNCTION_CONFIG_ARITY_MAX</a></code>, Boost.Function. </p>
<div class="refsect2">
<a name="id-1.7.2.4.4.7"></a><h3>
<a name="boost.overloaded_functionconstruct-copy-destruct"></a><code class="computeroutput">overloaded_function</code> 
        public
       construct/copy/destruct</h3>
<div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem">
<pre class="literallayout"><a name="id-1_7_2_2_1_5-bb"></a><span class="identifier">overloaded_function</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">function</span><span class="special">&lt;</span> <span class="identifier">F1</span> <span class="special">&gt;</span> <span class="special">&amp;</span><span class="special">,</span> 
                    <span class="keyword">const</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">function</span><span class="special">&lt;</span> <span class="identifier">F2</span> <span class="special">&gt;</span> <span class="special">&amp;</span><span class="special">,</span> <span class="special">...</span><span class="special">)</span><span class="special">;</span></pre>Construct the overloaded function object. <p>Any function pointer, function reference, and monomorphic function object that can be converted to a <code class="computeroutput">boost::function</code> function object can be specified as parameter.</p>
<p><span class="bold"><strong>Note:</strong></span> Unfortunately, it is not possible to support polymorphic function objects (as explained <a href="http://lists.boost.org/Archives/boost/2012/03/191744.php" target="_top">here</a>). </p>
</li></ol></div>
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<div class="refsect2">
<a name="id-1.7.2.4.4.8"></a><h3>
<a name="id-1_7_2_2_1_4-bb"></a><code class="computeroutput">overloaded_function</code> public member functions</h3>
<div class="orderedlist"><ol class="orderedlist" type="1">
<li class="listitem">
<pre class="literallayout"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">function_traits</span><span class="special">&lt;</span> <span class="identifier">F1</span> <span class="special">&gt;</span><span class="special">::</span><span class="identifier">result_type</span> 
<a name="id-1_7_2_2_1_4_1-bb"></a><span class="keyword">operator</span><span class="special">(</span><span class="special">)</span><span class="special">(</span><span class="keyword">typename</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">function_traits</span><span class="special">&lt;</span> <span class="identifier">F1</span> <span class="special">&gt;</span><span class="special">::</span><span class="identifier">arg1_type</span><span class="special">,</span> 
           <span class="keyword">typename</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">function_traits</span><span class="special">&lt;</span> <span class="identifier">F1</span> <span class="special">&gt;</span><span class="special">::</span><span class="identifier">arg2_type</span><span class="special">,</span> <span class="special">...</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span></pre>Call operator matching the signature of the function type specified as 1st template parameter. <p>This will in turn invoke the call operator of the 1st function passed to the constructor. </p>
</li>
<li class="listitem">
<pre class="literallayout"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">function_traits</span><span class="special">&lt;</span> <span class="identifier">F2</span> <span class="special">&gt;</span><span class="special">::</span><span class="identifier">result_type</span> 
<a name="id-1_7_2_2_1_4_2-bb"></a><span class="keyword">operator</span><span class="special">(</span><span class="special">)</span><span class="special">(</span><span class="keyword">typename</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">function_traits</span><span class="special">&lt;</span> <span class="identifier">F2</span> <span class="special">&gt;</span><span class="special">::</span><span class="identifier">arg1_type</span><span class="special">,</span> 
           <span class="keyword">typename</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">function_traits</span><span class="special">&lt;</span> <span class="identifier">F2</span> <span class="special">&gt;</span><span class="special">::</span><span class="identifier">arg2_type</span><span class="special">,</span> <span class="special">...</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span></pre>Call operator matching the signature of the function type specified as 2nd template parameter. <p>This will in turn invoke the call operator of the 2nd function passed to the constructor.</p>
<p><span class="bold"><strong>Note:</strong></span> Similar call operators are present for all specified function types <code class="computeroutput">F1</code>, <code class="computeroutput">F2</code>, etc (even if not exhaustively listed by this documentation). </p>
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<td align="right"><div class="copyright-footer">Copyright &#169; 2011, 2012 Lorenzo Caminiti<p>
        Distributed under the Boost Software License, Version 1.0 (see accompanying
        file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
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